<html>

<head>
    <title>js自动下载文件到本地</title>
    <script language="javascript" type="text/javascript">
        function InitAjax() {
            var ajax;
            if (window.ActiveXObject) {
                var versions = ['Microsoft.XMLHTTP', 'MSXML.XMLHTTP', 'Microsoft.XMLHTTP', 'Msxml2.XMLHTTP.7.0',
                    'Msxml2.XMLHTTP.6.0', 'Msxml2.XMLHTTP.5.0', 'Msxml2.XMLHTTP.4.0', 'MSXML2.XMLHTTP.3.0',
                    'MSXML2.XMLHTTP'
                ];
                for (var i = 0; i < versions.length; i++) {
                    try {
                        ajax = new ActiveXObject(versions[i]);
                        if (ajax) {
                            return ajax;
                        }
                    } catch (e) {}

                }
            } else if (window.XMLHttpRequest) {
                ajax = new XMLHttpRequest();
            }

            return ajax;
        }
        //js自动下载文件到本地 
        var xh;

        function getXML(geturl) {
            console.log(geturl);
            xh = InitAjax();
            xh.onreadystatechange = getReady;
            xh.open("GET", geturl, true);
            xh.send();
        }

        function getReady() {

            //console.log(xh.readyState); 
            if (xh.readyState == 4) {
                console.log(xh.status);
                if (xh.status == 200) {
                    saveFile("d:\dd.gif");
                    return true;
                } else {
                    return false;
                }
            } else
                return false;
        }

        function saveFile(tofile) {
            console.log(tofile);
            var objStream;
            var imgs;
            imgs = xh.responseBody;
            objStream = new ActiveXObject("ADODB.Stream");
            objStream.Type = 1;
            objStream.open();
            objStream.write(imgs);
            objStream.SaveToFile(tofile)
        }
        getXML("./苹果.txt"); 
        //js自动下载文件到本地结束
    </script>

</head>

<body>
    <form id="form1" runat="server">
        <div>
            <input type="button" value="124" onclick="getXML('')">
        </div>
    </form>
</body>

</html>